The invention relates to a method for layerwise production of a tangible object according to the preamble of claim 1. The invention also relates to a system for layerwise production of a tangible object. The invention furthermore relates to a controller for use in such a system, as well as to a computer program product, including program code portions for performing the function of such a controller.
Such a method is known. For example it is known from DE10256672A1 that the liquid reservoir has a transparent bottom plate whose upper side has a separation layer. In the space above the bottom plate there is a carrier plate which can be moved up and down. During its movement, the carrier plate can reach positions ranging from under the liquid level to above it. A firstly formed solid layer of the tangible object is adhered to the underside of the carrier plate. Consecutively formed solid layers are each adhered to a previously formed solid layer, respectively.
Each time after solidification of a new layer, the carrier plate together with the earlier solidified layers adhered thereon are moved upwards in order to separate the last formed solid layer from the separation layer of the bottom plate. Each time after such separation, the separated solid layer is moved to a predetermined position at a distance from the separation layer of the bottom plate for letting the liquid flow-in between the separated solid layer and the separation layer of the bottom plate. By solidifying a predetermined area of a layer containing the flow-in liquid, a successive solid layer of the tangible object is obtained.
The upward separation movement of the carrier plate requires an external force to be exerted on the carrier plate. This external force results in an increase of internal stresses in the tangible object being produced. Especially vertical tensile stresses in objects with varying cross-sections can become locally very high. If these stresses become too high, the object can deform, deteriorate or break. Since, for the known method, a fast separation requires the external force to be high, the internal stresses in the tangible object during such fast separation are high as well. Thus, a drawback of the known method is, that there are only limited kinds of objects that can be rapidly formed. Other kinds of objects, especially those with strongly varying cross-sections, can not be rapidly formed with the known method.